This invention is directed to thickened silicone oils in the form of silicone elastomers swollen into silicone gels, silicone pastes, or silicone powders.
Cross-links are junctions of polymer strands in a three-dimensional network. They may be viewed as long-chain branches which are so numerous that a continuous insoluble network or gel is formed.
Increasingly, platinum catalyzed hydrosilylation reactions are being used to form networks. They typically involve reactions between a low molecular weight polysiloxane containing several .tbd.Si--H groups, and a high molecular weight polysiloxane containing several .tbd.Si-vinyl groups, or vice versa.
Attractive features of this mechanism are that (i) no by-products are formed, (ii) cross-linking sites and hence network architecture can be narrowly defined, and (iii) hydrosilylation will proceed even at room temperature to form the networks. In the mechanism, crosslinking involves addition of .tbd.SiH across double bonds, i.e., .tbd.SiH+CH.sub.2 .dbd.CH--R.fwdarw..tbd.SiCH.sub.2 CH.sub.2 --R.
We have utilized this mechanism, but by employing some unobvious and unique modifications of the mechanism, we have been able to formulate a new range of product forms having new and unique properties and ranges of application.